The present invention relates generally to pressure relief valves and more particularly relates to valve arrangements for use in testing and draining fire suppression water sprinkler systems.
In a typical fire suppression water sprinkler system as installed in many buildings, an array of individual water sprinklers is supplied with water through a main conduit and various branch conduits. The individual water sprinklers are generally provided with a member that melts when the ambient temperature reaches a predetermined level indicative of a fire. The melting of the member opens a water sprinkler to spray water in order to suppress the fire. The individual water sprinklers are provided with meltable members so that the spray of water will hopefully be limited to the region of the building where the fire is present. In this way, the extent of water damage may be minimized.
After a fire, and especially during maintenance and renovation, it may become necessary to replace one or more of the individual water sprinklers. At such times it is desirable to be able to drain the system of water conduits, so that the removal of one or more of the individual water sprinklers (after the supply of water to the main conduit has been turned off and after the system has been drained) will not result in a flow of water through the fitting for the water sprinkler. Accordingly, it is conventional in the art to provide a valve which when opened will drain the water conduits of the system.
Such fire suppression systems also oftentimes have a switch or sensor that detects the flow of water in the conduits to indicate that even only one of the individual water sprinklers has opened. Since the flow of water in the conduits generally means that a fire is present in the building, the switch or sensor typically triggers a fire alarm or sends an appropriate signal directly to a fire department. Therefore, many fire codes require, and it is otherwise desirable, that the switch or sensor which detects the flow of water in the conduits be periodically tested. Accordingly, it has also become conventional in the art to provide a valve which enables the system to be tested by permitting a flow of water corresponding to the flow through only one individual water sprinkler that has been opened.
In addition, it is desirable (and sometimes required by the applicable fire code) to be able to visually observe the flow of water from the testing valve. Since the testing valve (and oftentimes the drainage valve) is frequently connected directly to a drain pipe, it is conventional to provide a sight glass downstream of the testing valve (and sometimes the drainage valve). It is, of course, possible to alternatively place a sight glass upstream of the testing valve. Also, since it is typically desirable to determine the pressure of the water upstream of the testing valve, prior to and during a test operation, it is conventional to provide a fitting or port to receive a pressure gauge upstream of the testing valve.
In fire protection systems, it is sometimes desirable or necessary (and may be required by local ordinance) to provide a pressure relief mechanism in the fire sprinkler system in communication with the arrangement of piping that supplies water (or some other fluid) to the individual sprinkler heads. In order to provide a pressure relief feature for a fire sprinkler system, it is known to provide a Tee fitting in the piping arrangement in communication with the sprinkler heads and to connect an inlet of a suitable, conventional pressure relief valve with the arrangement of piping through one of the openings in the Tee fitting. The outlet of the pressure relief valve is then directed as desired, either to a drain or outside of the structure being protected by the fire sprinkler system.
In one known arrangement, the outlet of the pressure relief valve is connected by way of another Tee fitting to a drain. The drain is in turn in communication with the arrangement of piping through a globe valve. In this way, when the globe valve is closed, and the pressure in the arrangement of piping remains below a predetermined value, the arrangement of piping may be maintained in a pressurized state. However, when it is desired to drain the system, the globe valve may be opened. In addition, when the pressure in the arrangement of piping exceeds the predetermined value, the pressure relief valve opens to direct the fluid in the arrangement of piping into the drain and thereby relieve the excessive pressure.
The use of separate pressure relief valves and drainage valves and testing valves results in significant time and expense during the installation of such plumbing. For example, in U.S. Pat. No. 5,103,862 issued on Apr. 14, 1992 to AGF Manufacturing, Inc., a separate pressure relief valve is provided in combination with a test and drain valve. The inlet of the separate pressure relief valve is provided in communication with an outlet of the test and drain valve. Preferably, the outlet of the pressure relief valve is provided in communication with the other outlet of the test and drain valve.
Accordingly, it is an object of the present invention to provide a pressure relief valve for a fire suppression water sprinkler system in which the pressure relief valve also permits a testing of the fire suppression water sprinkler system.
Yet another object of the present invention is to provide a valve arrangement for a fire suppression water sprinkler system which provides a pressure relief feature and a testing feature in a single valve.
Still another object of the present invention is to provide a valve arrangement for a fire suppression water sprinkler system which is relatively simple and easy to install and use.
Yet still another object of the present invention is to provide a valve arrangement for a fire suppression water sprinkler system having a pressure relief feature and a testing feature which is relatively inexpensive and relatively inexpensive to install.
These and other objects are accomplished by a valve and an arrangement for testing a fire suppression system having a pressure relief feature according to the present invention.
The arrangement according to the present invention comprises a conduit for supplying water to a plurality of sprinklers with a sensor provided for sensing the flow of water in the conduit. A valve is provided downstream of the sensor in communication with the conduit.
The valve according to the present invention comprises a valve housing having an inlet and an outlet. A valve member is biased at a predetermined amount toward a valve seat so as to maintain the valve in a closed condition unless and until the pressure at the inlet of the valve housing is greater than the predetermined bias of the valve member. The valve housing is provided with a restricted orifice corresponding to the flow through a single water sprinkler head so that when communication is permitted between the inlet and the outlet of the valve housing, the flow is restricted to correspond to the flow through the single water sprinkler head. An arrangement is provided to manually open the valve.
Preferably, a cam and lever mechanism is provided to pull the valve member away from the valve seat. In the preferred embodiment, the predetermined bias for the valve member is provided by a coil spring.
In operation, when the pressure in the conduit (i.e., the pressure in the inlet of the valve), exceeds the predetermined bias for the valve member, the valve opens to provide a pressure relief feature for the arrangement of sprinkler heads. When the valve member is manually moved away from the valve seat, the valve permits a flow through the valve corresponding to the flow through a single water sprinkler head. In this way, the sensor provided in the conduit upstream of the valve may be tested by determining whether the sensor triggers an alarm in response to a flow of water corresponding to the flow through a single sprinkler head.
Although the valve is restricted to only permit a flow through the valve corresponding to the flow through a single sprinkler head, the valve may also be used to drain the system, if desired, by manually opening the valve.